Intermittent Power Reduction While Driving At Steady Speed

[mshah]

Hello

I've recently purchased an old-generation Prius (2001) and am very pleased with it.

There is one problem that I have been unable to demonstrate to the dealership because it is intermittent, and of course will refuse to show up when I take the car on a test run with an engineer!

Problem is this:

When driving the car at a constant steady speed, at some random point in time, there is a sudden distinct reduction in power. You can sense that the car has suddenly become very sluggish and you have to push the accelerator pedal down a lot further to maintain the same speed/performance. After a few minutes the normal power/performance level recovers.

Although this seems occur at any speed, it seems to occur most at around 30mph, and usually when the car is running on purely Battery power.

Has anyone on this forum experienced this sort of rather annoying problem or have any ideas?

Many thanks.

[JerryW]

When driving the car at a constant steady speed, at some random point in time, there is a sudden distinct reduction in power. <snip>

Although this seems occur at any speed, it seems to occur most at around 30mph, and usually when the car is running on purely battery power.

1. What is the energy display screen showing at this point? It sounds as if you have simply run down the HV Battery

2. You might get more responses at the Prius-UK Yahoo group:

http://autos.groups.yahoo.com/group/Prius-UK

Regards

Jerry

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[mshah]

When driving the car at a constant steady speed, at some random point in time, there is a sudden distinct reduction in power. <snip>

Although this seems occur at any speed, it seems to occur most at around 30mph, and usually when the car is running on purely battery power.

1. What is the energy display screen showing at this point? It sounds as if you have simply run down the HV battery

Many thanks for the reply.

The energy display generally doesn't change. It continues showing that the car is running on the electric motor only. However, the power/performance level would have dropped significantly as explained. To me, it's as if the Battery has perhaps been discharged too much but that the petrol engine hasn't kicked in as it aught to have in order to compensate and hence the marked reduction in power. As explained, this is a rather random phenomenon - not happening predictably or all the time, but happening nevertheless (and difficult to demonstrate when you need to!)

Another observation in case it is related:

When placing the car in "P", sometimes the petrol engine switches on. My understanding is that in the "P" position, if the engine is running (and aircon and heating are off) then it is doing so to charge the traction Battery. In that case I would expect the energy display to indicate that the engine is charging the Battery. However, such an indication is not always present - most of the time there is no animation in any of the energy paths on the display when the car is in "P" but running. Hopefully, this is not a major problem but I would be interested to know if it this is what other members of the forum have observed with their Prius' (old model), and of course I'm wondering if this observation could be linked to my original issue raised in this post.

2. You might get more responses at the Prius-UK Yahoo group:

http://autos.groups.yahoo.com/group/Prius-UK

Thanks for that - will have a look.